The present invention relates to methods, control devices and computer program products for (near) synchronous control of networked lighting devices.
Networked lighting devices offer remote control of light effects that are to be rendered. As the number of networked lighting devices in a home, an office, etc. grows, new user demands arise. As an example, it is undesirable when a user executing a scene change results in the lamps in the ceiling pendants changing color before the lamps in the wall mounted luminaires change color. Although timed lighting commands in combination with a global clock used by all networked lighting devices can resolve this issue, this requires any of: increased processing overhead for controlling the networked lighting devices, additional or more complex components in networked lighting devices, etc. In a networked lighting system comprising multiple networked lighting devices, there is therefore a need for controlling such networked lighting devices (nearly) in-sync in a simplified manner.
The inventors have realized that in networked lighting systems, lighting control commands have a maximum length and as such only a limited number of networked lighting devices can be controlled to change color or intensity in a single command. When multiple networked lighting devices need to change color or intensity, multiple control commands are sent resulting in the controlled networked lighting devices adjusting their light output out-of-sync. It is an object of the present invention to provide a method, a device and a computer program product for (near) synchronous control of networked lighting devices. In a first aspect of the invention, a method is provided for near synchronous control of networked lighting devices, the method comprises receiving a target color point, in a target color space having a target color space resolution, and/or a target intensity level, in a target intensity space having a target intensity space resolution, and further receiving identifiers for networked lighting devices that are to be synchronously controlled to emit light based on the target color point and/or target intensity level. A color space is a specific organization of colors and can comprise, for example, all colors of visible light, all colors that can be rendered by the networked lighting device or all hues of the color red. A color space resolution is the granularity of a mapping of color points to the color space. For example, if the color space resolution is 3 bits, then 8 color points within the color space are selectable (e.g. purple, mauve, blue, green, yellow, orange, red, white). If the color space resolution is only 2 bits, then 4 color points within the color space are selectable (e.g. blue, green, red, white). If the color space resolution is 2 bits and the color space comprises all hues of the color red, then the color points that are selectable can be different from the previous example (e.g. pink, raspberry, crimson, carmine). Through color mapping, for example, a value can be associated with a color point (e.g. binary value “10” is associated with crimson) or a color point can be indicated by, for example, X,Y-coordinates in a color space. Similar examples will be valid for the intensity level, intensity space and intensity space resolution.
The method further comprises determining that a target control command based on the received identifiers of the networked lighting devices and the received target color point and/or the received target intensity level will exceed a maximum control command length. Specifications for control commands (e.g. ZigBee Light Link specifications) or network limitations (e.g. maximum packet size in WiFi) place a limitation on the size of a control command. This results in the fact that the identifiers of a limited number of networked lighting devices can be comprised in a single control command. The control command will further comprise color and/or intensity information that is used to control the light output of the networked lighting devices. A control command may further comprise overhead, such as a prefix, message sequence numbers, etc. When not all networked lighting devices can be controlled through the same control command, multiple control commands are typically sent and this results in the networked lighting devices not changing their light output synchronously.
The method further comprises:
In an embodiment of the method according to the invention, the approximate color space is equal to the target color space and/or the approximate intensity space is equal to the target intensity space. In a further embodiment the approximate color space is not equal to the target color space and/or the approximate intensity space is not equal to the target intensity space; and determining an approximate color space resolution is based on the received target color point and/or wherein determining an approximate intensity space resolution is based on the received target intensity level. It can be beneficial to lower the color space resolution, yet remain in the same color space. For example, when the color associated with the target color point is visually close to the color associated with the approximate color point (e.g. the target color point is blue out of: purple, mauve, blue, green, yellow, orange, red, white; and the approximate color point is blue out of blue, green, red, white). Yet it can also be beneficial to determine an approximate color space that is not equal to the target color space. For example, when the target color space comprises colors that cannot be rendered by the networked lighting devices, a different color space can be determined.
In an embodiment of the method according to the invention, the method further comprises determining the color difference between the received target color point and the current color point and/or the intensity difference between the received target intensity level and the current intensity level, of the networked lighting devices that are to be controlled; and determining an approximate color space resolution is further based on the color difference and/or wherein determining an approximate intensity space resolution is further based on the intensity difference. This embodiment is especially beneficial as, for example, a color change from red to crimson can be better facilitated by an approximate color space comprising all hues of red than by an approximate color space resolution comprising all colors of visible light.
In an embodiment of the method according to the invention, receiving a target color point and/or a target intensity level comprises receiving both a target color point and a target intensity level, and the method further comprises determining that the color difference between the received target color point and the current color point is below a predetermined color difference threshold; wherein determining the approximate color space resolution comprises determining the approximate color space resolution to be zero; and wherein the control command comprises the identifier of the networked lighting devices that are to be controlled and the approximate intensity level. In a further embodiment of the method according to the invention, receiving a target color point and/or a target intensity level comprises receiving both a target color point and a target intensity level, and the method further comprises determining that the intensity difference between the received target intensity level and the current intensity level is below a predetermined intensity difference threshold; wherein determining the approximate intensity space resolution comprises determining the approximate intensity space resolution to be zero; and wherein the single control command comprises the identifier of the networked lighting devices that are to be controlled and the approximate color point. These embodiments are particularly beneficial as by determining the color space resolution or intensity space resolution to be zero, because respectively the current color of light emitted by the networked lighting devices is close to or the same as the target color point or the current intensity of light emitted by the networked lighting devices is close to or the same as the target intensity level, no approximate color point respectively no approximate intensity level is comprised in the approximate control command. Minor differences in color and/or intensity of light emitted by a networked lighting device are hardly visible to the human eye.
In an embodiment of the method according to the invention, the method further comprises:
In an embodiment of the method according to the invention, the method further comprises:
In an embodiment of the method according to the invention, the networked lighting devices are part of a mesh network. An example of a mesh network is a ZigBee network.
In a second aspect of the invention, a control device is provided for synchronous control of networked lighting devices, the control device comprising:
In an embodiment of the control device according to the invention, the first interface is an Application Programming Interface (API) and the second interface is a mesh network interface. Such an implementation can, for example, be provided through a bridge device that interfaces a first network, such as a Local Area Network, over which the API is offered and a second network, such as a ZigBee network, over which the control commands to control the networked lighting devices are controlled.
In a third aspect of the invention, a computer program product is provided for synchronous control of networked lighting devices, the computer program product comprising computer program code for executing the method of any one of claims 1 to 10 when the computer program code is run on a computer device.
It shall be understood that the (computer implemented) method, the control device and the computer program product, have similar and/or identical preferred embodiments, in particular, as defined in the dependent claims.
It shall be understood that where it is referred to synchronicity, this comprises near synchronicity, as explained in the summary above.
It shall be understood that a preferred embodiment of the invention can also be any combination of the dependent claims with the respective independent claim.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.
To assist understanding of the present disclosure and to show how embodiments may be put into effect, reference is made by way of example to the accompanying drawings in which:
In
By lowering the resolution of the color space or the intensity space, more networked lighting devices 111, 112, 113, 114 can be controlled through one control command 160. In this example, the color space resolution has been adapted such that a color point is provided as a 12 bit RGB color value and the intensity space resolution has been adapted such that an intensity level is provided at a 12 bit depth. An approximate color point 170 and an approximate intensity level 180 are comprised in the approximate control command 150.
Although the approximate color point and the approximate intensity level may not match the target color point and target intensity level, this is preferred over the use of multiple control commands. The approximate color point and the approximate intensity level can be selected to be as close to the target color point and the target intensity level as possible.
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The first approximate color space resolution 610 simply divides the gamut of colors into four colors that can be represented by the X,Y-coordinates. Each of the X,Y-coordinates in the first approximate color space resolution 610 replaces four X,Y-coordinates in the target color space resolution 600. In the second approximate color space resolution 650 a more sophisticated approach is used. As certain color differences are easier to distinguish to the human eye than others. Table 1 below provides an overview, however this is a mere illustration of the principle. Given the simplification used in this example, the effect of certain color differences not being noticeable is only partially true in this example providing a 4 to 2 bit color depth conversion. Application of this principle at higher color depths (e.g. 24 bit color depth) provides more practical application, yet would be overly complex to present here.
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Although in the examples specific bit depths have been used in explaining the invention, this does not exclude other bit depths, ranges, values, etc.
Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.
In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.
A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
Any reference signs in the claims should not be construed as limiting the scope.
Number | Date | Country | Kind |
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15161276.9 | Mar 2015 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2015/075779 | 11/5/2015 | WO | 00 |
Number | Date | Country | |
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62076837 | Nov 2014 | US |